This work introduced an efficient method to synthesize a unique and inexpensive CoNi-LDH with high electrocatalytic activities, and it will be conductive to developing other catalysts toward OER. In addition, these excellent electrochemical performances expect the potential application for the O₂ supply to cathodic molecular oxygen activation.

Abstract

Coupling of anodic oxygen evolution reaction (OER) and cathodic molecular oxygen activation (MOA) addresses the issues of conventional electrochemical advanced oxidation process (EAOP), such as parasitic anodic oxygen evolution and potential formation of halogenated byproducts in the presence of halogens, while the key to this process is an anodic O₂ supply generated from the hysteretic OER. Herein, we have constructed crystalline-amorphous cobalt–nickel-layered double hydroxide (CoNi-LDH) nanosheets by simple one-step ultrasound treatment as OER catalysts. Benefiting from the partially amorphous and porous structure, the CoNi-LDH heterojunction shows an overpotential of 260 mV to achieve a current density of 10 mA cm⁻². Besides, it also exhibits excellent electrochemical stability in basic media, which is significantly superior to the corresponding layered monometallic hydroxides. This work provides inspiration for optimizing the catalytic activity of OER electrocatalysts through combining crystalline and amorphous heterojunction, expecting the potential application in OER/MOA process.